The formula to determine the number of bars of signal strength to display on iPhone 4, iPhone 3GS, and iPhone 3G has been improved by the iOS 4.0.1 Software Update. Though, there will be no visible change in the real signal strength, but the bars on iPhone will point towards it more specifically.

Multitasking is available only with iPhone 4 and iPhone 3GS, as all features are not compatible with all devices. But, this iOS 4.0.1 upgrade has unintentional side-effects, which has wrecked havoc with the iPhone's photo albums.

Though, the actual photographs are not affected by this chaos, as the users can still see them in their entirety, if they browse through them in a full-screen mode.

The problem has hit the iPhone 3G owners the hardest. The 3GS and iPhone 4 users shared that the problem can get fixed with a simple reboot. But, 3G users are not lucky enough.

The sort order for photos has also been changed. While some folders sort by date was taken instead of alphabetically, some other doesn't seem to be sorting by means of any visible order.